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Rotwang ~ UltiBot’s ~ Vic
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Rotwang
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Joined: 15 Jun 2004
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Location: Vic


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This pair of MMC’s is made from the original batch of circuit boards Brett had made years ago.
They are development prototypes and the arrangement we had was that I would build the rolling bot and Brett would provide the electronics.
Back then we thought big Robots would take off locally.
To do a production run now is I suspect no longer worthwhile with sidewinders etc out there.

To calculate how much these are worth? A huge amount of Brett’s time, Lots for setting up $ to print only one board [it had a mixture of BMC MMC & IBC] and paying high prices for small numbers of components.

On the other hand the IBC has done well. Cool

The MMC’s scare me, I am not even game to suggest plugging them in the amount of magic smoke they contain must be enormous and I would not like to be the one to let that out. Smile

Post Wed Jul 19, 2006 9:06 am 
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Knightrous
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I wouldn't mind getting a pair of the bare boards and assembling them myself. I'd have to get Brett or Glen to do the surface mount components for me as my SMD soldering skills are not that good, but the rest I reckon I could do.

I'm looking at buying a pair of Victor 883's, so the MMC's would be a nice overkill factor and still fit into my design, while allowing expansion for larger classes...
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Post Wed Jul 19, 2006 9:22 am 
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Rotwang
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Your still interested in the MMC’s hmm is that why you seemed to be taking so much interest in Mells daughter? Wink Smile

Post Wed Jul 19, 2006 9:35 am 
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Knightrous
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LMFAO... Laughing No... I never actually thought of that...

We have the BMC's here, but they are a bit big to put into a featherweight Wink I think I could wedge the MMC's in though without too much hassle and they could be used in a lightweight or a middleweight in the future...

I always liked the MMC's, they seemed to be in the middle ground to me. Big controllers, but not too big. The price was a little high back a few years ago when I enquired with Brett, but I'm confident now that I could assemble and test most of the controller myself, minus the SMD work.
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Post Wed Jul 19, 2006 9:51 am 
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Rotwang
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You have the BMC’s! I didn’t know that, does that mean Vertex is getting some attention? Smile

Post Wed Jul 19, 2006 11:21 am 
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Spockie-Tech
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The MMC's arent likely to become commercially available unless someone throws lots of money (or equivalent) at me.. or we suddenly see a big need for them in the Australian RoboWars game

There are a total of 7 boards in existance from the first PCB production run..

4 are completely built, 2 are working (The two Gary are running). I have another 2 here that will be repaired without too much more work I hope.

The remaining 3 unbuilt PCB's *could* be assembled, but to release them to anyone else to do so would just ensure a heap of "how do I xx ?" questions to me, which would take up as much of my time as building them myself would have anyway.

Plus, the parts arent the sort of thing you buy from dick-smith or jaycar, so you would have to either harass Jason (which means giving them to people would then take up his time as well as the builder tried to obtain parts for them), or you would have to a pay a fortune to get the parts from places likie DigiKey overseas.

You would then also need to build the seperate "uMOB" brain board, which requires programmed AVR Microprocessors (meaning you need an AVR Programmer), and understand how the whole thing works well enough to debug it.

Sorry to sound negative, but these *aren't* dick smith kits we are talking about here. They are version 0.1 prorotypes constructed with parts uncommon in Australia and requiring greater than average soldering skills (Those heavy 4oz tracks are a bitch to solder properly) and an understanding of power-electronics and switching to get working. Plus, if you make a little mistake, you release a *lot* magic smoke (16-32 fets worth !) and have to start all over again.

Finally, 85%+ of the cost of a speed controller is in the parts, the labour (from an experienced assembler) is only a small part of the price, so you would save very little by "DIY". Thats why we never released kits for the IBC. The price would be so close to the assembled one it wasnt worth it, and it would just create a heap of "warranty" hassles as people send back their "I Assembled the FETs with dads plumbing iron and now it doesnt work, your design sucks" controllers.

With good commerically made controllers like the OSMC, SideWinders etc all available ready-to-roll at reasonable prices, the presence of a few unbuilt circuit boards in my draw should not be looked at as a free ticket to some "cheap" high power controllers - They wouldnt be.
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Post Wed Jul 19, 2006 11:44 am 
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Spockie-Tech
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Dont worry gary.. I still have another set of BMC boards in the draw if we suddenly need them Smile

I gave Andrew the partially built versions to look into using as a sort of offb-oard "Fet-Brick" driven by wires from an IBC.

The onboard control-circuitry on a BMC would require significant modification to get working, since it was designed for built in temperature and current limiting via an additional microprocessor and code that doesnt exist yet.

There is *some* possibility that it could be used as a remote Fet-Brick, just using the slab of fets on heatsinks, with the high-power tracks on the circuit boards, and surgically disabling the rest, but I'm not confident how well it would perform under heavy load with the gate-control wires being that long.
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Post Wed Jul 19, 2006 11:54 am 
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Rotwang
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Joined: 15 Jun 2004
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Oh that’s good, so be warned out there. We have the ultimate doomsday option; we can build a stupidly powerful heavyweight pushy bot. Sabertooths chassis is still under the bed in the spare bedroom. Very Happy

Post Wed Jul 19, 2006 12:24 pm 
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Valen
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could you move the HIP chips over, and supply them with pwr and signal from the ibc?
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Post Wed Jul 19, 2006 12:24 pm 
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Spockie-Tech
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That might work better.. The missing current/thermal limiting circuitry lies between the PWM input connector from the uMOB and the HIP chips. Its job was to modify the PWM drive if the limit conditions were met.

Everything from the HIP chips forwards should be workable, so you fitted hip chips, then wired the low-power hip-chip control lines back to a gutted IBC, you might have a working combination.

Tell you what Aaron. If you think you're up to building an MMC yourself, see if you can get that idea working with the BMC's for Andrew. If you can pull that off then I'll consider releasing a set of MMC circuit boards to you. Cool
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Post Wed Jul 19, 2006 1:25 pm 
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Knightrous
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*Puts on MacGyver voice*
With this trusty paperclip and orange peel, I'll build this MMC speed controller Cool
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Post Wed Jul 19, 2006 3:13 pm 
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Rotwang
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Started on Pyrobot, after seeing the terrain he will have to cope with we are going for 2 drive wheels and a single caster.
This gives us a 2,4,6 wheel drive combination to experiment with.
Bulldoze is 6, our drum bot which will probably just get called Ultidrum is 4 and now Pyrobot is 2 and a caster.

Other progress Ultidrum just needs paint and final assembly.
We upgraded to 200-watt motors but the wheels will have to wait till later.

Post Mon Jul 31, 2006 12:26 pm 
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dyrodium
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Just out of interest, by "caster" you don't mean the tiny crappy wheelychair type do you? Methink's they'd quickly suck in off road driving! Very Happy
How were you guys planning on doing your pyrobot's flamethrower?
I've been working out some designs with a car fuel injection nozel and nichrome wire, but not sure if it'd work or not. Confused
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Post Mon Jul 31, 2006 1:33 pm 
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Daniel
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When you said wheel chair castor the first thing I thought of was the castor wheel I used to bolt onto wheel chairs for kids in third world countries. The wheel chairs were designed for the same sort of terrain as the ultibots, the same sort of weight and knowing kids, the same sort of speeds.
So you can get heavy duty off road castors. I just can't remember where they came from.

Post Mon Jul 31, 2006 2:10 pm 
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Rotwang
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Joined: 15 Jun 2004
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I made my own out of an electric scooter head and a 6”x2” pneumatic wheel same as King Pin runs.


Almost all of the weight will be on the drive wheels.

Haven’t started on the flamethrower yet apart from a pop cons ting of a few propane bottles, one of those $20 butane stoves (probably a good basis for a featherweight), a car IPG solenoid valve, some car injectors and some fittings and a piece of pipe that will hopefully look like a suitable Darlek exterminator.Very Happy


Last edited by Rotwang on Mon Jul 31, 2006 3:17 pm; edited 1 time in total

Post Mon Jul 31, 2006 3:04 pm 
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